![Health Highlights: Aug. 13, 2021](http://media.assettype.com/healthday%2Fimport%2F27123021%2Forigin.jpg?w=480&auto=format%2Ccompress&fit=max)
Here are some of HealthDay's top stories for Friday, Aug. 13:
A 3rd shot for people most vulnerable to COVID-19. As the Delta variant spreads, the U.S. Food and Drug Administration on Thursday authorized a third "booster" shot of coronavirus vaccines for people with weakened immune systems. Read more
The Delta variant & breakthrough cases in the vaccinated. Reports of COVID cases among the fully vaccinated are everywhere, but just how common -- and serious -- are these cases? Experts sort through the data. Read more
New study shakes up what's known about metabolism. The notion that a person's metabolism starts to slow in middle age, adding to weight gain, just doesn't hold up under scientific scrutiny, new research shows. Read more